The present invention relates generally to dispensers for liquid soap and other viscous materials. More particularly, the invention relates to devices that automatically detect the presence of a user's hand and dispense a predetermined quantity of the viscous material.
Wall-mounted dispensers for liquid soap or other viscous material, such as hand lotion, are widely used in public and commercial buildings. Often, the dispenser will be constructed having a support base attached to the wall. A pivotal cover is closable on the base to define a housing in which components of the dispenser are contained. The viscous material is located in a storage bag or the like provided as part of a disposable cartridge located in the housing's interior. The disposable cartridge includes a tube forming a peristaltic pump through which the viscous material is dispensed.
Many dispensers of the prior art operate manually, wherein a lever is moved by the user when a quantity of the viscous material is desired. Alternatively, the dispenser may be adapted for automatic operation. In devices of this type, a photoelectric detection circuit is typically provided to sense the presence of a user's hand near the dispenser. When the hand is detected, the device actuates the peristaltic pump to thereby release a predetermined quantity of the viscous material.
Due to the use of electrical and electromechanical components therein, automatic dispensers require a source of power in order to operate. In some cases, the dispenser may be adapted for AC operation from a conventional wall outlet. Often, however, AC operation has been seen as undesirable, in part because it limits the potential locations at which the dispenser can be installed.
In order to overcome the disadvantages of using AC power, dispensers have been provided that operate from battery power. These dispensers, however, have typically employed general purpose batteries, such as D-cells. Because such batteries are relatively large, the dispenser housing must be appropriately sized. In addition, batteries of this type are often subject to frequent replacement.